/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.startup;

import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import org.apache.naming.StringManager;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Hashtable;

/**
 * Concrete implementation of the <strong>UserDatabase</code> interface
 * that processes the <code>/etc/passwd</code> file on a Unix system.
 *
 * @author Craig R. McClanahan
 */
public final class PasswdUserDatabase implements UserDatabase {

	private static final Log log = LogFactory.getLog(PasswdUserDatabase.class);
	private static final StringManager sm = StringManager.getManager(PasswdUserDatabase.class);

	/**
	 * The pathname of the Unix password file.
	 */
	private static final String PASSWORD_FILE = "/etc/passwd";

	/**
	 * The set of home directories for all defined users, keyed by username.
	 */
	private Hashtable<String, String> homes = new Hashtable<String, String>();

	/**
	 * The UserConfig listener with which we are associated.
	 */
	private UserConfig userConfig = null;

	/**
	 * Return the UserConfig listener with which we are associated.
	 */
	@Override
	public UserConfig getUserConfig() {
		return userConfig;
	}

	/**
	 * Set the UserConfig listener with which we are associated.
	 *
	 * @param userConfig The new UserConfig listener
	 */
	@Override
	public void setUserConfig(UserConfig userConfig) {
		this.userConfig = userConfig;
		init();
	}

	/**
	 * Return an absolute pathname to the home directory for the specified user.
	 *
	 * @param user User for which a home directory should be retrieved
	 */
	@Override
	public String getHome(String user) {
		return homes.get(user);
	}

	/**
	 * Return an enumeration of the usernames defined on this server.
	 */
	@Override
	public Enumeration<String> getUsers() {
		return homes.keys();
	}

	/**
	 * Initialize our set of users and home directories.
	 */
	private void init() {
		BufferedReader reader = null;
		try {
			reader = new BufferedReader(new FileReader(PASSWORD_FILE));
			String line = reader.readLine();
			while (line != null) {
				String tokens[] = line.split(":");
				// Need non-zero 1st and 6th tokens
				if (tokens.length > 5 && tokens[0].length() > 0 && tokens[5].length() > 0) {
					// Add this user and corresponding directory
					homes.put(tokens[0], tokens[5]);
				}
				line = reader.readLine();
			}
		} catch (Exception e) {
			log.warn(sm.getString("passwdUserDatabase.readFail"), e);
		} finally {
			if (reader != null) {
				try {
					reader.close();
				} catch (IOException e) {
					// Ignore
				}
			}
		}
	}
}
